An ultrasonic camera has been developed with sufficient resolution, sensitivity, and convenience of operation for use in a variety of diagnostic applications. Research and development into the fundamental processes of ultrasonic image generation have been undertaken with a view toward unambiguous interpretation of clinical images. Recently, a significant improvement in image quality has been obtained with a diffuse isonification technique; this improvement allows subtle differences in tissue characteristics to be determined. This work will result in expanded usefulness of focused ultrasonic transmission imaging in clincial medicine.